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**thelightiger****Guest**

Find the sum and provide your answer in a fraction

1+i/2-1/4-i/8+1/16+i/32-...

This is a geometric series.

What is its common ratio?

What is the formula for the sum of a geometric series?

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**George,Y****Member**- Registered: 2006-03-12
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Note the common ratio is a complex number.

**X'(y-Xβ)=0**

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**Alg Num Theory****Member**- Registered: 2017-11-24
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George,Y wrote:

Note the common ratio is a complex number.

It still works, provided the modulus of the common ratio is less than 1.

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